Hereinafter, a copier as an example of a recording device will be described as an example. As represented by Patent Document 1 or 2 described below, in the copiers, as a transport unit for a recording material, a belt transportation device is frequently used. In the belt transportation device, there is a problem of skew of an endless belt that is wound between a driving roller and a driven roller. When the skew of the endless belt occurs, the recording material in the middle of a transport process has a slope, and accordingly, disturbance or slope occurs in an image acquired from performing recording for the recording material. In addition, when the skew of the endless belt is neglected, the edge of the endless belt is damaged, and thereby a decrease in the transport force, disturbance of transport, or stop of transport occurs.
Accordingly, as shown in Patent Document 1 or 2, generally, a belt skew correction device is built in the belt transportation device, and whereby the occurrence of the above-described inconvenience due to skew of the endless belt is reduced.    [Patent Document 1] U.S. Pat. No. 3,082,452    [Patent Document 2] Japanese Unexamined Patent Application Publication No. 2002-251080